Risk assessment the potential occurrence of anthrax outbreaks in the Republic of Tatarstan

Aim. To assess the risks of potential anthrax outbreaks based on a retrospective analysis of the epizootic situation for this infection and inventory data on the number of stationary anthrax-unfavorable sites in the Russian Federation using the case of the Republic of Tatarstan.

Methods. A retrospective analysis of data on animals with anthrax in the Republic of Tatarstan and the inventory of permanently unfavorable sites for this infection in the Russian Federation was carried out by using veterinary reporting documents for the period between 1914 and 2018. The epizooticity index of anthrax-unfavorable sites was determined by the formula: EI=(n×t)/(N×T), and the effectiveness of specific prevention of the infection was determined according to the guidelines. Analyzes were carried out using statistical methods.

Results. The analysis of the results of the conducted studies showed that between 1914 and 2018, 2037 group and single animals infected with anthrax on the territory of the Republic of Tatarstan, 1208 stationary unfavorable sites for this infection were registered. When assessing the risks of the potential occurrence of anthrax among animals of the Republic of Tatarstan, it was found that 69.8% of the territory of the republic (every third settlement) is permanently unfavorable for anthrax and has serious risks of a possible re-infection of animals with this infection, therefore all livestock of animals once a year vaccinated against anthrax. A study of more than 11,000 blood serum samples of animals vaccinated against anthrax according to this scheme revealed that the titer of anti-anthrax antibodies decreases 1:2 and 1:4 below the level that protecting the animal from infection with the causative agent of this infection in 20% of animals after 6 months, and in 60% after 12 months after vaccination. This creates high risks of anthrax in animals and people in disadvantaged areas since the anthrax pathogen is transmitted from an infected ¬animal to a person by mistaken autopsy of dead animals or the processing of carcasses of animals, hidden carriers of the anthrax pathogen. With this in mind, in regions with high risks of anthrax, it was confirmed the need for introducing two vaccinations per year into the prevention scheme of this infection in animals and monitor the post-vaccination immunological status, which will allow them to maintain high immunity throughout the year and promptly eliminate the focus of infection.

Conclusion. It was found that 69.8% of the territory of the Republic of Tatarstan (every third settlement) is permanently unfavorable for anthrax and has high risks of anthrax outbreaks in animals; it was shown the need for complex anti-anthrax measures, including two-time vaccination of animals during the year, to reduce the risks of infection of animals and the population with the causative agent of this infection.